Proteins containing copper, molybdenum, and iron-sulfur clusters, which are involved in biological electron transport, hydrogen and nitrogen metabolism, and redox transformations of metabolites, will be studied with the aim of understanding the basis of activity in molecular structure. Resonance Raman spectroscopy will be utilized, to monitor the vibrational frequencies of the molecular entities at the protein active site, and the spectra will be analyzed with the aid of appropriate model compounds and normal coordinate calculations. EXAFS (extended x-ray absorption fine structure) analysis will be used to help characterize the structure and dynamics of copper proteins.